Controllable apparatus for radius cutters



Jan. 20, 1959 A. F. HARTWIG 2,869,431

CONTROLLABLE APPARATUS FOR RADIUS CUTTERS Filed. June 13, 1955 FIG.|. Y

4 Sheets-Sheet 1 Arm-27oz $31? I #4271444 Jan. 20, 1959 A. F. HARTWI,G' 2,369,431

- CONTROLLABLE APPARATUS FORRADIUS CUTTERS Filed June 1s,' 1955 4 Sheets-Sheet 2 ip-mans;

Jan. 20, 1959 A. F. HARTWIG v2,869,431

' CONTROLLABLE APPARATUS FOR RADIUS CUTTERS Filed June 13, 1955 4 Sheets-Sheet 3 Jan. 20, 1959 A. F. HARTWIGI,

CONTROLLABLE APPARATUS FOR RADIUS CUTTERS Filed June 15, 1955 4 Sheets-Sheet 4 retested Jan. 20, M959 CONTROLLAELE APPARATUS FOR RADIUS CUTTERS Aihert F. Hartwig, University City, Mo., a ssignor to Mclllionneii Aircraft Corporation, St. Louis, Mo., a corporation of Maryland Application .iune 13, 1955, Serial No. 514,929 9 Claims. (Cl. 90-19) This invention relates to improvements in controllable apparatus adapted for use With tools designed for cutting or otherwise forming a radius on the peripheries of form blocks and the like.

The apparatus hereof has particular utility in the mazing of form blocks which are blocks or tools over which a part is formed when using the guerin process of rubber forming. While the foregoing statement is given for clarity of terminology, it is not intended that the apparatus shall be so limited as not to include other uses for which it may have application. However, since all form'blocks require a radius that is tangent to two intersecting faces, as a face and a side Wall, it is necessary to use a cutting or forming device to perform this function. Generally such devices have relied upon hand manipulations and visual methods which are not accurate.

Therefore, a principal object of this invention is to rovide apparatus which will-operate to maintain the proer tangency relationship between the cutter and tWo intersecting surfaces of a form block.

it is also an object hereof to provide apparatus which when properly adjusted will automatically maintain the desired relationship between cutter and work and thereby avoid the objections of visual operations and resulting necessary hand finishing.

it is an object of the invention to provide improved apparatus which is readily adaptable to existing power tools and may be used for such materials as aluminum, kirksite, Masonite and steel, as well as many others.

Another object is to provide apparatus which will anticipate bevel angles which vary from a straight line or a particular contour, or which have changing conditions from open angles to closed angles, and will compensate and continue to hold the work in the proper position for radius cutting under the varying conditions.

Uther objects are to provide apparatus which will be simple to operate and use, and will be economical to manufacture.

The apparatus of this invention consists in cooperating slides or feelers which are located in predetermined relation to a radius cutter and against which the work is moved in such a manner that the feelers function to maintain the work in proper radius cutting position as it is moved past the cutter. The apparatus also consists in means for adjusting the work engaging feelers to ac commodate different radii of cutters.

The apparatus further consists in such parts, combinations of parts and sub atsemblies as will hereinafter be pointed out, reference being had to the accompanying drawings for a detailed understanding of a preferred form thereof.

In the drawings:

Fig. 1 is a plan view of one with the present apparatus;

Fig. 2 is a front elevational view of the same;

Fig. 3 is a side elevational view of the same;

Fig. 4 is a side elevational view, partly in section, the

form of power tool equipped present radius cutting control apparatus as seen along line 4--4 of Fig. l; V

Fig. 5 is a side elevational view opposite to the view of Fig. 4 of the present apparatus;

Fig. 6 is a top plan view of the apparatus;

Fig. 7 is a longitudinal sectional elevational view of the apparatus as seen along line i7 of Fig. 6;

Fig. 8 is a transverse sectional elevation view of the apparatus as seen along line 8-8 of Fig. 7;

Fig. 9 is a detailed sectional view taken at line 9-9 in Fig. 7;

Fig. 10 is a longitudinal sectional plan view of the apparatus as seen along line 10-10 of Fig. 7;

Fig. 11 is a schematic view of the apparatus showing its operation; and

Fig. 12 is a further schematic view of the apparatus showing a different operation thereof.

In Figs. 1, 2 and 3 the power tool or machine 10 with which the present apparatus 11 is associated comprises a work table 12 supported by a suitable frame and leg structure 13. An opening in the work table '12 is provided with an insert 14 having a center opening through which the cutter element 15 projects to a position above the plane'of the surface of the table 12 (see Fig. 7). The cutter element 15 is suitably connected to a spindle 16 of a drive motor 17, the motor 17 being suitably mounted underneath the work table 12 on a raising and lowering mechanism shown generally at 18. This portion of the power tool 10 forms no part per se of the present invention, as other machines may be used with the apparatus 11 hereof.

ing knob 27 mounted therein by a nonthreaded The preferred form 'of apparatus includes (Figs. 4 to 5 inclusive) spaced frame members of right and left hand formation, but each having a slotted base flange 20 (Figs. 4 and 6) and an uprightly and angularly inclined guide member 21. The base flanges 20 are secured to the work table 12 by suitable bolts 22 so that the apparatus may be adjusted to the proper position upon Work table 12 relative to the radius cutting element 15. Each inclined guide member zlt'has'an inclined guide way 23 to receive slide blocks 24 which. are connected at the upper ends by a common cross head 25 (Figs. 8 and 9) which etfects simultaneous movement ofthe blocks 24. The guide members 21 are connected at the'o-uter end (Fig. 4, 7 and 8) by a fixed thrust plate 26 which carries an adjustsleeve 28 and connected to a thrust screw 29 which, in turn, has driving connection with the cross head 25 for the slide blocks 24. Thus, turning of the knob 27 will result in up or down displacement of the slide blocks 24 in the longitudinal direction of inclined ways 23 of the guide members 21.

The lower ends of the slide blocks 24 are suitably con nected to a carrier 30 arranged in parallel relation to the plane of work table 12 so that, upon adjustment of the height of the slide blocks 24 through the knob 27, move the blocks 24 and the connected carrier 30 away from or approach the work table 12 Without changing the parallel relationshipof the blocks 24 or the carrier 30 thereto The sliding blocks 24 are connected rigidly to the cross head '25 and the carrier 30 and the sliding clearance between the blocks 24 and the ways 23 is kept at a minimum so that the carrier 30is rigidly supported for all positions of the blocks 24. Thus, since the angular relationship of blocks 24 to carrier 3t does not change, it follows fromthe geometry of this condition that the carrier 30 will have to remain parallel to base 12. Figs. 4, 5, 6, 7 and 8, the carrier 30 is shownsupport ing. a'lower feeler 31 movable in a longitudinal horizontal groove 32 and an upper feeler 33 movable in a similar are closed bylower' cap 35 and upper cap 36, but the 3 upper cap 36 is formed with a longitudinal slot 37 (Figs. 6, 7 and 8) having a forward closed end 38. There are two feelers 31 and 33 since the apparatus is more accurate in the forming of radii on form blocks which vary from open to closed angles, and, too, the cutting action is to the inner end 41 where the end 42 of a companion feeler member 43 is located. The rearward end of feeler member 43 is formed with a slot 44, and the extreme end of the slotted portion carries a cross pin 45 to form the connecting means for the end of a piston rod 46. Again as best seen in Fig. 7, the rearward end portion 47 ,of the lower cap 35 is made thicker and an angle bracket 48 is secured thereto so that the end 47 and the bracket 48 form a mounting for the fiange 49 of a power unit such as the cylinder 50 containing a piston 51 on the inner end of rod 46. The exposed portion of piston rod 46 is encircled by a spring 52 which abuts the bracket 48 and the end of the companion feeler member 43. The parts described above are those on the carrier 30 and move up or down with the carrier 30, depending upon the adjustment imparted to the carrier by the knob 27.

The two part form of the upper feeler 33 and companion part 43 is provided for a purpose to be described. The ends 41 and 42 are formed with aligned recesses to receive one or more (two being shown) small springs 53 which normally tend to hold the feelers apart, as shown in Fig. 12, and also allow for limited lost-motion movement of one part relative to the other part. This relative movement is utilized to control the power unit which constitutes a booster system connected with the upper feeler parts 33' and 43. The control which is part of the booster system includes a bracket 55 carried on feeler part 43 and having spaced side plates 56 which support a housing 57 in which a microswitch 58 is mounted with its switch actuating button 59 exposed. The feeler 33 carries a switch actuating finger 60 arranged to engage the microswitch button 59 as the springs 53 urge the feeler 33 outwardly of groove 34 relative to companion feeler 43. The microswitch 58 is electrically connected to a junction box 62 by the two wire cord 63, and electrical current is fed to the box 62 by the main two wire cord 64. The box 62 is mounted on a solenoid type actuator unit 65, and this unit is suitably functionally connected to a controllable valve 66 in a manner well understood. The schematic views of Figs. 11' and 12 indicate the solenoid 65 connected to a valve plunger 67 which controls the compressed air supply conduit 68 (see Figs. and 6). The valve .66 is connected by conduit 70 to the outer end of cylinder 50. A bleed valve 71 of any suitable type is inserted in conduit 70 and functions to bleed the air at a slow rate from the cylinder 50. However, when air is supplied from valve 66 the greater volume overcomes the rate of bleeding at valve 71 so that the piston 51 is displaced. The inner end of cylinder 50 has an open port 72 to avoid vacuum lock.

The coordination of the feelers 31 and 33, together with the companion feeler 43, is obtained through a cam device 73 (see Figs. 7, 11 and 12) pivotally mounted in the cap portion 47 by pivot element 74. The device 73 has a cam lobe 75 and an arm 76 formed with an elongated slot 77 which receives a cross pin 78 carried in the region of slot 44 in companion feeler 43. The action of this device 73 is governed by the motion of feeler 43 and the latter serves to rotate or swing the cam device 73 about its pivot 74, thus changing the position of the cam lobe 75 relative to the cam follower 40 on lower 4 feeler 31. The mechanical movement of cam lobe 75 is to produce coordinated small increments of displacement of feeler 31 for large increments of displacement of feeler 43. This, then, allows the cam follower 40 to exert on the cam lobe 75 a restraining or binding force when a work piece, such as the form block B, is against the feeler 31. In other words, the cam lobe 75 has a profile which develops a mechanical disadvantage so that the feeler 31 may frictionally bind the feeler system against movement, until the power of the booster system is used. Furthermore, the contour of the lobe 75 is such that it moves the pattern block B inwardly and outwardly relative to the cutter member 15 as the bevel angle of the surface 80 changes so that the edge of the block being rounded is always rounded tangentially to the two adjacent surfaces thereof. Such a booster system includes a power unit such as the air cylinder 50 and piston 51 therein operatively connected to the feeler 43 through rod 46, and the control switch 58 which energizes the solenoid actuator 65 for the air control valve 66.

The apparatus above described operates in the following manner, with respect to the form block B having the closed angle bevel side wall 80 and the top face 81 which is placed against the work table 12: The apparatus 11 is secured to the work table 12 in such position that the lower feeler 31 is directly above the cutter element 15 (Fig. 7). The location of the block B has nothing to do with this step. The cutter has the cutting radius contour 82 which it is desired to form on the margin 83 of block B tangent to the side wall 80 and top face 81. Now, with no form block B in position and with the air and electric current on, the feeler 33 will be extended to the limit of its lost motion range by springs 53 to close the switch 58 and energize the solenoid 65 to open control valve 66 for air fiow through conduit 70 to drive piston 51 to the left or outwardly, assisted by spring 52, and displace the feeler 43 outwardly (Figs. 7 and 11). This action is passed by the springs 53 to the feeler 33 and eventually ends when it is held from further movement by finger so that the switch 58 opens. Leftward or outward movement of the feeler 43 swings the cam device 73 counterclockwise to move feeler 31 outwardly in the same direction, but the feeler 33 will extend beyond feeler 31. The apparatus is now in a position with both feelers 31 and 33 extended a maximum amount.

A block B to be radius formed is moved toward the feelers 31 and 33, usually being taken to have contact first established with the upper feeler 33 to break the contacts in switch 58 and cut off the air pressure supply on piston 51 so that there will be no bind by feeler 31 and rightward or inward movement of feeler 43 is resisted only by spring 52. When valve 66 is closed (Fig. 12) air in cylinder 50 is released by the bleed action of valve 71 and the feelers 33 and 43 can recede if forced. At the proper position, the block B engages the lower feeler 31 putting a force on it which acts then to drive cam follower 40 against cam 75 to bind the cam device 73 as explained. At this time the apparatus will be in the condition shown in Fig. 11, and it will remain in this condition so long as the angle of the bevel wall is constant. The lack of variation in the bevel angle will not require follow-up feeling by feeler 33 to indicate to feeler 31 whether the bevel angle is closing or opening at a given time should the bevel angle change (Fig. 12) to a more closed angle, the feeler 33 will be allowed to extend itself until the switch 58 is closed. Closure of switch 58 admits air to the cylinder 50 to drive the rod 46 outwardly. The motion of feeler 33 is very small,'for it is necessary to keep the lower feeler 31 in proper adjustment for uniform results, but since feeler 31 acts to bind the cam device 73 it requires considerable force from piston 51 to move feeler 43 toward feeler 33 to again open the switch 58. The

feelers 3 1, and 33 and 43 continue to keep step-by-step pace with each other in guiding the block B. In efifect, feeler 33 reads changes in the bevel angle or contour of the side Wall 80 and feeler 31 follows the reader on a very much reduced movement and binds the system to all but large forces by the piston 51. The above operation is dependent upon making the contour of cam 75 in relation to its pivot '74 impose a bind or mechanical disadvantage on counterclockwise movement of arm 76. For example, when block B engages the tip of feeler 31, theoperator holding the block in this position must exert just enough force to maintain this contact with feeler 31. The feeler 31 is forced rearwardly to cause follower 40 to engage cam lobe 75, thereby fixing the limit of counterclockwise movement of arm '76. The momentary fixed limit for arm 76 also limits the action of spring 52 in forcing feeler 43 outwardly (to the left in Fig. 11) so that feeler 31 has effectively limited movement of feeler 53 outwardly by binding upon cam lobe 75. This combination of forces on feeler 43 leaves feeler 33 free to respond to the trend of the bevel angle at wall 8%) under the resilient action of springs 53. Thus, the switch 53 can be closed or opened as feeler 33 reads the bevel angle and moves accordingly.

If the bevel angle at side wall dtl of the block B changes to an open angle, that is to an angle greater than 90 to the face 81, the feeler 33 will read this change by breaking the contact at switch 58, thus cutting off the air supply at conduit 70. Then the thrust exerted by the operator to move the block B so as to keep it engaged by both feelers will be opposed only by spring 52 which can be manually overpowered to force feelers 33 and 43 inwardly so that the block may be kept against the feeler 31. At this time the friction bind or mechanical disadvantage at cam lobe 75 is overcome by the force being exerted on arm 76 to rotate it clockwise, and the device 73 swings in a clockwise direction to permit the block B to force or adjust the feeler 31 to a new position in which follower 40 binds upon cam lobe 75 which maintains the radius forming by cutter element 15 tangent to wall 8% and face plane 81 of block B. This action of the apparatus will continue with feeler 33 reading the changes and effecting coordinated adjustments of follower feeler 31. Should the bevel angle change toward a closed angle the spring 52 will attempt to push feeler t3 outwardly, but the arm 76 will not allow this due to the bind on the cam by follower ll This limit on movement of feeler 43 is important so that t1 e switch 53 can be closed by outward lost-motion movement of feeler 33 and air will be fed behind piston 51 to force feeler 43 outwardly overcoming the friction bind at cam lobe 75 until the switch 53 is opened. This force by piston 51 will be transmitted through arm 76 and cam 75 to feeler 31 to force the feeler 31 to push the block B away. This power action is needed to oppose the operators tendency to keep pushing the block B into the cutter.

The present apparatus possesses a desirable of adjustability through the function of knob .7 adaptable for use with cutter elements 11 .g ting contours 82 of different size. I the shown, the position of the carrier 3b with it: l 35 upon the worl: table indicates the smallest con ur 32 which may be used. For larger contour cutter el 15, the snob 27 is turned to raise the carrier position. This raising of the carrier associated assembly a like amount. PC; a anism 7.8 for the cutter motor it may be lower the cutter element 35 below the wowhen the power tool is not in use.

The foregoing description relates to a preferred embodiment of the apparatus, but it shouldbe understoodthat the principle of the invention can be applied to different forms of apparatus and it is intended to cover all such forms of apparatus coming within the scope of the following claims.

What is claimed is:

l. Controllable apparatus for form block radius cutting power tools having a cutter element with a radius cutting contour,'said apparatus comprising first feeler means positioned to slidably engage the form block and to follow changes in the contour thereof, second feeler means positioned to engage the form block and to follow changes in the contour thereof, a movable control device engaged by said second feeler means to bind said control device in any given moved position, a companion feeler part having lost-motion connection with said first feeler means; said control device being connected to said companion feeler part, and a power unit connected to said companion feeler said power unit being energized responsive to the lost-motion movement between said companion feeler part and said first feeler means for overriding the bind on said control device to adjust the relative positions of said first and second feeler means.

2. Apparatus for guiding a variable bevel angle surface a form block past a radius cutting element having a radius cutting contour, said apparatus comprising a first form block contour reader mounted for longitudinal movement, said reader including aligned companion feelor parts having lost-motion connection for relative movement therebetween and resilient means associated with said feeler parts to extend said lost motion connection, a second form block contour reader including a follower feeler adjacent said first contour reader, a cam device connected to said first contour reader and pivoted adjacent said follower feeler, said cam device having a cam lobe adapted to be in binding engagement with said foller to frictionally retain said first contour reader, t contour reader adjusts longitudinally when the .ent of said second reader senses a variation in the form block bevel angle to thereby allow said feeler parts to be extended, said resilient means and controllable booster means operatively connected to cause said longitudinal movement of said companion feeler parts of said first contour reader, and means actuated by the relative movement of said feeler parts to cause said booster means to overpower said binding engagement and project said first reader.

3. Apparatus for locating a variable bevel angle surface of a form block adjacent a radius cutting contour element with two intersecting faces tangent to the contour of the radius cutter, said apparatus comprising a longitudinally movable form block contour reader including companion feelers having a lost-motion connection, resilient means connected between said companion feelers to urge one thereof outwardly of the other, a follower feeler adjacent said contour reader and longitudinally movable in parallelism therewith, a motion coordinating device pivoted adjacent said follower feeler and having a binding engagement therewith and an operating connection with said contour reader, engagement of said follower feeler with the form block serving to effect a bind upon said motion coordinatin device to retain one of said contour reader companion feelers against longitudinal movement while allowing lost motion movement of the other companion feeler, and booster means operatively connected with said companion feelers, said booster means moving one of said companion feelers in response to said lostmotion movement between said companion feelers for overpowering the bind on said motion co-ordinating device and to thereby adjust the position of said contour reader and follower feeler to variations in the form block bevel angle.

4. Apparatus for locating a variable contour surface of a form block adjacent a contoured radius cutter element, said apparatus comprising a pair of form block contour feelers arranged to be movable in longitudinal parallelism, one of said feelers including two parts having a lost-motion connection, resilient means connected between said two parts to urge one part outwardly relative to the other part, a motion co-ordinating device having a frictional binding engagement with the other of said feelers and an operating connection with said other part of said one feeler, said binding engagement serving to retain said pair of feelers in fixed positions of adjustment, and overpowering booster means operatively connected with said two parts of said one feeler, said booster means responding to lost-motion movement of said one part outwardly of the other part for overpowering the binding engagement with said other feeler and to readjust the positions of said pair of feelers with variations in the form block contour.

5. Apparatus for locating a form block adjacent a contoured radius cutter comprising form block contour reading means having a part movable in response to changes in the form block contour, form block contour follower means movably positioned adjacent said reading means and adapted to maintain a steady guiding contact with the form block, motion co-ordinating means connected to said reading means to move therewith, said follower means having a binding engagement with said motion co-ordinating means to restrain movement thereof when pressure on said follower means predominates over said reading means whereby said movable part will move into engagement with said form block, said binding engagement maintaining the steady guiding contact on said follower means, power means operatively connected to said reading means to overpower the motion restraining effect of the binding engagement of said follower means with said motion co-ordinating means, and control means operable by movement of said movable part in response to changes in the form block con tour, said control means being connected to said power means to determine operation thereof.

6. The apparatus of claim 5," wherein said control means includes electrically energized means connected to said power means and circuit make and break means responsive to movement of said movable part.

7. The apparatus of claim 5, wherein said motion coordinating means comprises a cam device having an arm connected to said reading means and a cam lobe engaged by said follower means.

The apparatus of claim 5, and elevation adjusting means connected to bodily shift the apparatus in elevation relative to the location of the radius cutter.

9. Apparatus for controlling radius cutting of form biocks, said apparatus comprising means supporting two for block feelers for movement toward and from exit positions, thereon, one of said feelers constituting a for follower, resilient means associated with said reader urging it toward the extended position, power booster means connected to said reader driving it toward the extended position, means on said reader responsive to movement of the reader due to form block contour changes to control said power booster means, and feeler movement co-ordinating means in said supporting means having operating engagement with said two feelers, whereby movement of said reader feeler is transmitted to said coordinating means and movement of said co-ordinating means controlls the movement of said follower feeler.

References Cited in the file of this patent UNITED STATES PATENTS 2,674,232 Mason Apr. 6, 1954 2,787,l97 Gordon Apr. 2, 1957 FOREIGN PATENTS 565,470 Great Britain May 11, 1939 .i bloca' contour reader and the other constituting 

